I'm assuming you are looking for a printed solution then? Didn't really see it being asked, but it sounds like you already have an engraver for your crystals, so assume you're going to do a printed design. Your best bet would be to order plastisol transfers, or if you lock in a set in stone amount for the quantity and sizes of shirts, have them screen printed. Plastisol transfers are similar to feel and quality as a regular screen printed shirt (uses the same process), except you get the transfer on a sheet of paper and heat press each shirt as needed. Research some of the plastisol transfer companies if you're going that route before you order. F&M used to be one of the top recommendations, but it sounds like they have been messing up as of late.